Brain transcriptomic response of the threespine stickleback Gasteroteus aculeatus to predator cues. Gasterosteus aculeatus

In this study, we used whole genome comparative oligonucleotide microarrays to investigate the brain transcriptomic response to predator cues using the threespine stickleback, Gasteroteus aculeatus. We showed that exposure to olfactory, visual and tactile cues of a predator (rainbow trout, Oncorhynchus mykiss) for six days resulted in subtle but significant transcriptomic changes in the brain of sticklebacks. Gene functional analysis and gene ontology (GO) enrichment revealed that the majority of the transcripts differentially expressed between the fish exposed to predator cues and the control group are primarily related to antigen processing and presentation (involving primarily the major histocompatibility complex (MHC)), transmission of synaptic signals, brain metabolic processes, gene regulation, or visual perception. Pathway analysis identified synaptic long-term depression, RAN signaling, relaxin signaling and phototransduction as the top four pathways that were over-represented. Overall design: Adult fish were placed in six different 26L tanks with three fish per tank in a partially recirculating flow-through system. Half of the tanks were assigned to the control group and the other half to the experimental group.10 samples were selected for microarray analysis. The ten samples comprised five biological replicates in the experimental group (fish exposed to predator cues) and five biological replicates in the control group (fish not exposed to predator cues), and were evenly distributed across tanks. The cDNA labeling (single color), hybridization, washing and scanning steps were performed in the NimbleGen microarray gene expression service department.

本研究以三刺鱼（Gasteroteus aculeatus）为实验对象，采用全基因组比较寡核苷酸微阵列技术，探究其大脑转录组对捕食者线索的响应。研究发现，将三刺鱼暴露于捕食者虹鳟（Oncorhynchus mykiss）的嗅觉、视觉与触觉线索环境中6天，可使其大脑出现显著但细微的转录组变化。通过基因功能分析与基因本体（GO）富集分析发现，捕食者线索暴露组与对照组间的差异表达转录本，主要与抗原加工呈递（主要涉及主要组织相容性复合体（MHC））、突触信号传递、脑代谢过程、基因调控或视觉感知相关。通路分析结果显示，突触长时程抑制、RAN信号通路、松弛素信号通路及光传导通路为富集程度最高的前四大通路。

实验总体设计：将成年三刺鱼饲养于6个不同的26升水箱中，每箱投放3尾鱼，饲养系统为部分再循环流通系统。其中3个水箱被划分为对照组，剩余3个为实验组。本研究共选取10个样本进行微阵列分析，实验组（暴露于捕食者线索的三刺鱼）与对照组（未暴露于捕食者线索的三刺鱼）各包含5个生物学重复，且样本在各水箱中均匀分布。cDNA标记（单色彩）、杂交、洗涤及扫描步骤均由NimbleGen微阵列基因表达服务部门完成。